Federal government forecasts major earthquake in Chicago area

Let me confess at the outset that the headline above is perhaps a bit misleading. But, of course, my objective is to attract eyeballs to this blog, and anything short of a blatant falsehood is fair play.

The headline does not say the feds are predicting a major quake for the Chicago area. What we’re talking about here is a forecast, not a prediction. There’s a big difference.

In his book “The Signal and the Noise” (above), Nate Silver, the brilliant numbers-cruncher, says this:

A prediction is a definitive and specific statement about when and where an earthquake will strike: a major earthquake will hit Kyoto, Japan, on June 28.

Whereas a forecast is a probabilistic statement, usually over a longer time scale: there is a 60 percent chance of an earthquake in Southern California over the next thirty years.

With that difference in mind, we note that the U.S. Geological Survey forecasts (but doesn’t predict) a major earthquake of at least 6.75 magnitude once every 75,000 years within a 50-mile radius of Chicago.

By comparison, the forecast for such a quake in the Anchorage, Alaska, area is once every 30 years, on average. For San Francisco, it’s once every 35 years. In Los Angeles, once every 40 years.

I bring up all of this simply to recommend Silver’s book. It’s full of amazing stuff about forecasts, predictions, odds and averages as they pertain to such diverse subjects as economics, baseball, politics, poker, weather and earthquakes.